The Hanf numbers of stationary logic. II. Comparison with other logics.
Saharon Shelah · Notre Dame Journal of Formal Logic · 1991
We show the ordering of the Hanf number of ω ( wo) (well ordering) ω (quantification on countable sets), £ ωω (aa) (stationary logic), and second-order logic has no more restraints provable in ZFC than previously known (those independence proofs assume CON(ZFC only).We also get results on corresponding logics for £\, μ .